The "differences" are more to age than anything else. Singer made small modifications to the machines as time passed, and you'll see that with many models. My husband did three 401A's, and they all were a bit "different" as they were a very early one, middle and a very late one, but ALL the same model number. Some differences were cosmetic, some internal. None made a big difference when using the machine.
Same with the 301 - the "301" is a very early model - as Singer decided to put the A designation on after this model went into production. So the 301 and 301A have differences due to time - they were not marketed together as two slightly different models.
BTW - my husband has also gone a 301 and two 301A's, and all three have differences, but not as drastic as those with the 401A group.
Last edited by Macybaby; 03-24-2014 at 04:26 AM.